This structure is to be found in the fields near Eland Lodge at Newborough. It seems rather abandoned - without even a track going to it - so I guess it isn't used much now.
My first assumption was that it was a kiln, but someone who knows about these things says it's a old cold-store (fridge) or ice-house. However, I still think it's a kiln, and probably a brick-kiln.
It doesn't seem to be mentioned in Joy Ellis' history of the village.
There was some burnt wood in it there when I saw it, even though it was cold to the touch. Maybe now, locals use it occasionally as a giant chiminea...?!